The present invention relates to ratchet wrenches and, more particularly, to powered ratchet wrenches.
Conventional powered ratchet wrenches generally employ an electrical or pneumatic motor coupled to a ratchet mechanism through a transmission. The output shaft of the motor turns a transmission input shaft, and the output shaft of the transmission turns a crankshaft. The crankshaft eccentric rotation oscillates a ratchet yoke. The movement of the ratchet yoke causes a pawl to engage and rotate the ratchet spindle or tool head of a ratchet mechanism to rotate so that a bolt, nut, or other threaded part engaged therein is tightened or loosened.
The ratchet yoke comprises a large component within the head of the wrench, and necessitates a wrench head that is larger than would otherwise be necessary if the yoke could be eliminated. It is desirable to provide a wrench head as small as possible to reach into restricted spaces, and any measure that reduces the size of the wrench head is considered an important advance in the art.